Cover for oil storage tanks



March 21,\1933.- R, s WO OD 1,902,103

COVER FOR OIL STORAGE TANKS Filed April 15, 1930 2 SheetsSheet l H il l March 21, 1933. R. s. TWOGOOD 1,902,108

COVER FOR OIL STORAGE TANKS Filed April 15, 1930 2 Sheets-Sheet 2 r 78 70a Z9 Z0 I Hm '1 73 v )2 Av Wi -k 22 :2

- IN VE N TOQ 244 P16 .5. Twvaaa oil, thereby excluding the air cover and the oil surface.

Patented Mar; 21, 1933 UNITED STATES PATEr wales rec RALPH S. TWOG OOD, OF SAN FRANCISCO, CALIFORNIA oovnn ron OIL STORAGE TANKS Application filed April 15, 1930. Serial xiv/444,426.

The hereinafter described invention relates to the storage of inflammable'liquids, such as crude oil,

fuel oil and the like, and the exclue' sion of oxygen from contact with the surface 5 of these fluids Within the container as a supporter of ticularly the combustion thereof; being parapplicable to the storage of oil in" between the Another object of my invention is to provide a unitary type of cover construction for oil tanks of large storage capacity, such as concrete faced earthen reservoirs, which will float on top of the oil and which through the integrity of the liquid seal formed will assure the elimination of serious conflagration by exclusion surfaces.

of oxygen between the oil and cover A further object of my invention is to provide a plurality of water holding pans as a cover for inflammable liquid within a holder which will continuously reside at the liquid level and which when filled with water .will

serve to reduce the temperature of the liquid content and keep down the escapement of its volatile constituents. V

A further object of my invention is to pro.- vide a cover and system of handling oil with in a tank or holder in which the inlet and outlet of water into the tank will determine the oil level and thewater' will serve as a medium to float the oil into contact with a water tight flexible jointed cover composed of units made of a relatively light steel plate and which may be inexpensively constructed, thereby making possible the wide spread use of my new and novel type of cover as an eflective means of safety against fire at a nominal cost.

7 Another objectjof my invention is to provide a structure of cover which will carry water over substantially the entire exterior surface thereof m a ed pans,

plurality of flexibly jointin fact, a water cover forthe oil under-side of the cover and the surface of the stored within the tank and to float the water containing cover on the top of the oil surface so that it will always be in contact therewith in preventing the ingress of air between the oil, as a supporterof combustion, the blank et of water on the top of the cover also acting asdan element of protection against fire hazar s.

In order to fullyunderstand my invention, reference is made to the accompanying drawings in which, Fig. 1, is a plan view of the 'em' bodiment of my invention as applied to "a large oil containing earthen reservoir or holder with concrete faced interior, the flexible jointed water holding pans ofmy construction being shown as extending longitudinally across-the width of the holder, the inlet pipes for filling and discharging the oil there-' from as well as the water inlet and outlet pipes as used for floating theoil into contact with the under-side of the cover being shown. Fig. 2 isa sectional'elevation taken on line 2-2, Fig. 1, showing the structure of wooden columns, joists, stringers and sheeting upon which the flexible pans are mounted, the wooden structure servingto sustain the'cover when there is little or no oil in the holder as in initially filling it or when the liquid level has been lowered temporarily as occasion may demand for cleaning, the oil weir box I for maintaining the oil level against the under-side of-my new and novel cover being shown, a,

Fig. 3 is a broken plan view of a portion of the side of the holder showing how th ends of the pans comprising my cover reside relative to the top inside contour of the holder and the pipe outlets at the pan ends used for controlling the level of water there- 9 in being shown leading into an annular trough around the top of the'holder.

Fig. 4 is a sectional end view of the flexibly jointed pans of my construction as set together being taken on line 1-4, Fig. 3.

'Fig. .5 is an enlarged sectional end elevation of the flexible ointed connection of the pans of my construction showing the water level therein up to the mouth of the pipe pan outlet and below the flexible connection 5 this view also showing the liquid seal effected between the surface of the oil in its contact with the under-side of the pan units of my improved cover.

and showing the water pipe line for supply-.

ing the holder with water as used to float the oil level up in contact with the under-side of the cover, also the water weir box.

Referring to the drawings, numeral 10 denotes my flexible jointed pan constructed cover as a whole and numeral 11 indicates the earthen concrete faced holder over which it resides. Numeral 12 denotes the columns of the wooden super-structure upon which my cover 10 resides, while 13 shows the joists thereof and 14: the stringers upon which the woodensheeting 15 rests. The sheeting upon which the pans of my cover 10 reside is laid with open joints 16, as shown in Fig.5, so that the oil will have no difficulty in passing through to contact the under-side of cover 10. Cover 10 as shown is composed of a series of thin metal pans preferably of steel on account of its cheapness and same may be galvanized to prevent corrosion.

The pans when set together provide a unitary construction, the pan units being indicated by numeral 10a as shown in Fig. 5; the pans have bent up sides and ends as denoted at 10a1 and 104112, respectively, and their edges welded or otherwise sealed to form them into water holding vessels capable of floating. The pan sides 10a1 are provided with a clearance between them, as noted at X, andare held together along their top side edges in: flexibly jointed engagementby the edge cover cap 10a3 by rivets 104:4. Thecap 10a3 serves as a water sealing joint against the ingress of rain. The separation X provides a vent for the discharge of any gas residing at the surface of the oil so that it may make its exit to waste without being held or trapped as an active inflammable agent, thereby materially reducing. the fire hazard from this source. The pan ends are all provided with overflow pipe connections 10(15, which serve to maintain a predetermined head of water in the pans, as shown at Y, Fig. 5, so that excessive rainfall cannot reach the water flexible oint cap 10a3 but instead will. be carried off to waste in the concrete drain gutter 17 encompassing the top of the holder 11, through the outer ends of the overflow connections 10a5.

In this manner the pans serve as floating elements comprlsmg the cover 10 flexibly olnted to compensate movement between them in accommodating their bottom faces to the surface of the oil 1n assurlng the 1ntegrity of the liquid seal. therebetween. A

metal coping 18 is provided around the upper concrete rim 19, of the holder 11, so that storm water will be directed into the pans of cover 10, where it can be led to waste through pan pipes 10a5, thereby assuring that the periphery of the cover in its movable engagement with the. inner surface of the concrete rim 19. of holder 11 will be water tight. In making the movable engagement of cover 10 with rim 19, I carry out the edges of the woodensheeting 15 to fit the contour of holder'll and cover the surface of sheeting 15 a distance back from the pan ends 104112 with thin steel liner plate 20, which serves asa chafing plate in protecting the surface of sheeting 15 against movement of the pans of the cover 10 in compensating themselves to the surface of the oil within the holder 11 in effecting the liquid seal of my invention. Numeral 21 denotes the oil weir box of holder 11 through which the oil contained within holder 11'is discharged. The pipe line 22 carries the oil out of weir box 21 to a pump, not shown, from where it is distributed as demands-require.

The discharge 'ofthe oil from holder 11 into the weir box 21 through pipe 22 in the present embodiment of my invention occurs by displacement occasioned by water pumped into holder 11 at the bottom thereof through the pipe line 23 raising the body of oil so that its top surface contacts the under-side of the pans of cover 10. A funnel shaped outlet pipe 24 carries the oil out of holder 11 into weir box 21 from a point closely adjacent to but immediately underneath the liquid seal as'made between the surface of the oil and the under-side of cover 10 so that the seal will not be impaired at any time.

The handling of the water as used for governingthe height of the oil lever in holder 11 is controlled through water weir 25. Weir 25 is supplied from the discharge line 26 of a pump, not shown, overflowing through the weir gate into pipe line 27 which carries to the bottom of the holder 11, preferably near the center thereof. Holder 11 is filled with oil through the main supply pipe line 28.

In some instances in the use of my improved holder or reservoir structure, it is desirable to use the entire holding capacity thereof for the storage of oil, in which event I would dispense with the use of water as a medium with which to bring the surface of the oil in contact with the under-side of the cover in effecting the exclusion of air therebetween employing only the oil of the holder for this purpose,

I contemplate grounding the pans of my cover 10, so as to give a conductor of zero potential to the entire surface of the oil which my pan structure covers. This I would do, generally speaking, by running suitable I grounding wires from the ends of the pans to ground terminals. The grounded metal cover 10 of my construction gives additional protection against dangers from direct or indirect lightning.

The reservoir of my structure offers the safest protection possible to obtain for the inflammable liquid contained therein by reason of the certain exclusion of the air against the liquid surface afiorded.

I desire it to be understood that the embodiment of my invention as herewith illustrated and described is typical only of its construction and functioning and that its new and novel features and advantages are equal 1y applicable to any holder or tank whether constructed of steel concrete or earth wherein oil is stored and as such its inflammability offers a fire hazard.

Other means of controlling the inlet and outlet of the oil within holder 11 may be resorted to by me, suchrmeans requiring,. however, that the liquid seal between the surface of the oil in'the holder and the bottom of its floating cover 10 will always be maintained.

Minor changes may be made in the physical embodiment of the invention within the scope of the appended claims without de- J parting from the spirit thereof.

I claim:

1. A cover for an oil storage reservoir comprising in combination a plurality of pan units connected together to form a unitary water holding structure, means for maintaining a level of water in said units, a passage between said units for the discharge of gas,

and a head of water for floating said water containing and gas discharging cover on the surface of the oil in said container.

2. A cover for an oil storage reservoir comprising 1n comblnatlon a plurality of water carrying units, means for joining said units together, a vent at the juncture of said units for the discharge of gas, means for carrying water under head in said units, and means for exchanging oil for water within the confines of said reservoir in the maintenance of an oil seal against the bottom of said units.

3. In a cover for an oil reservoir or the like, a plurality of sheet metal pans, connecting joints between said pans, said joints having a seal for preventing the ingress of water into said pans and a passageway therebetween for the discharge of gas, and means for maintaining water in said pans at a predetermined level, said pans forming together a unitary floatable water carrying and gas discharging cover.

In witness whereof, I have hereunto set my hand at San Francisco, California, this 5th day of April, 1930. q

RALPH S. TWOGOOD. 

